This invention relates to tufting machine yarn tension rolls and more particularly to the mounting of such rolls so that the rolls may be disengaged rapidly in the event of an accident and for threading the yarn between the rolls.
Yarn tension or puller rolls are corrugated rolls used extensively in tufting machines especially those having a pattern attachment of the feed roll type including a yarn guiding tube bank having tubes of unequal length for conveying the yarn from the various feed rolls to the needles. The tension or puller rolls act to supply yarn to the needles at uniform tension despite the difference in path length traveled by the yarn through the tubes.
The tension rolls are mounted in pairs and supported at their ends in bearing brackets. Each roll pair of the prior art is supported at each end in a two-piece bracket with the cooperating brackets bolted together. The center distance between the rolls are adjusted by shims placed between the two pieces of the bracket.
This arrangement presents a safety hazard if the fingers of an operator are inadvertently engaged between the corrugated rolls. A safety feature provided by the prior art comprises the use of a plastic guard about the rolls to prevent the inadvertent insertion of fingers. The guard can be pivoted for threading of the rolls and includes a micro-switch and circuitry for shutting the machine when the guard is lifted. However, it has been found that the electrical circuit and thus the safety device is overridden in practice in attempts to save time when threading the rolls. With the prior art roll bracket construction when something is caught between the rolls, the machine must be stopped to remove it and the bolts released by unscrewing. The releasing of the bolts takes time and the injury can thus be extensive.